Means for releasably latching members in a well installation



Jan. 13, 1970 3,489,439

MEANS FOR RELEASABLY LATCHING MEMBERS IN A WELL INSTALLATION Filed March 6. 1968 N W.- \N. WORD, JR

2 Sheets-Sheet 1 FIG. I

6 B mm a Qmw M nm mum WW M m INVENTOR WILLIAM W. WORD M, I I 0. BY (1 ATTORNEYS.

Jan. 13, 1970 w. w. woRDfJR I 3, 39

MEANS FOR RELEASABLY LATCHING MEMBERS IN A WELL INSTALLATION Filed March 6, 1968 I 2 Sheets-Sheet a FIG. 2

& {I74 I76 454 I56 I84 I62 I60 I32 I I48 I 30 I30 Q r'l82 I50 .j I44 28 "1-5 3 I42 2 I52 I36 I40 INVENTOR F 3 WILLIAM w. WORD BY Md ,W

ATTORNEYS.

United States Patent C) 3,489,439 MEANS FOR RELEASABLY LATCHING MEMBERS IN A WELL INSTALLATION William W. Word, In, Houston, Tex., assignor to Armco Steel Corporation, Middletown, Ohio, a corporation of Ohio Filed Mar. 6, 1968, Ser. No. 710,876 Int. Cl. F16] 21/08 US. Cl. 285-143 8 Claims ABSTRACT OF THE DISCLOSURE In well installations, a member, such as a tubing hanger, is axially movable through an axial bore in another member, such as a head member. An intermediate member, such as a tubing hanger spider, is interposed in the axial bore between the tubing hanger and the head member. Latching means is provided to selectively latch the tubing hanger with the tubing hanger spider to prevent axial movement of the tubing hanger and to selectively unlatch the tubing hanger from the tubing hanger spider whereupon the tubing hanger can be axially withdrawn from the bore. Actuating means cooperates with and, in elfect, controls the latching means.

The latching means can advantageously comprise a latching groove on the tubing hanger and a series of freely radially movable pins through the tubing hanger spider to engage in the latching groove. The actuating means can advantageously comprise a series of actuating screws radially threaded through the head member and an annular actuating gland member axially movable in the bore. When the actuating screws are run into the bore, they move the actuating gland axially to, in turn, push the pins radially inwardly and into the latching groove. When the actuating screws are run out of the bore, the tubing hanger can be axially moved through the bore, thereby pushing the pins radially outwardly to disengage them from the latching groove.

This invention relates to improvements in well installations and more particularly it relates to a novel means for releasably latching together, a plurality of telescopically arranged well members.

In the typical well installation, a head member is provided with an upright or vertical bore therethrough and at least one, and sometimes several, casing hangers are mounted within such bore. Each casing hanger supports a suspended casing string with the various casing strings being concentrically telescoped one within the other. A tubing hanger is also provided within the bore of the head member, such tubing hanger supporting at least one, and sometimes multiple, tubing strings which project vertically downward through the innermost casing string. The tubing hanger, with the tubing string or strings suspended therefrom, is customarily lowered into position within the bore of the head member by a handling string and once the tubing hanger has been so situated and is properly suspended within the head member, the handling string is removed, the blowout preventers are removed, the bonnet is applied to the head member, and the master valve means or Christmas tree is connected through the tubing hanger with the suspended tubing string or strings. In some instances, the tubing hanger is supported directly by a shoulder means on the head member while in other instances the tubing hanger is supported by a tubing hanger spider positioned in the bore of the head member.

In installations of the type described hereinabove, some means must be provided for camming or otherwise urging the tubing hanger downwardly for proper compres- 3,489,439 Patented Jan. 13, 1970 sion of any sealing devices therebeneath, and additionally, some means must be provided for preventing the tubing hanger from being blown upwardly out of the well installation. When the tubing hanger is supported directly by the head member, so that the cross-sectional dimension of the tubing hanger is substantially equal to the cross-sectional dimension of the bore in the head member, anchor screws can be run through the head member to engage with a portion of the tubing hanger for s'erving the functions just described. An example of an arrangement of this type is shown in my prior Patent No. 3,062,565, dated Nov. 6, 1962. However, while such an arrangement can be utilized when the cross-section of the tubing hanger is substantially equal to the crosssection of the bore in the head member, it cannot be readily utilized in an instance where the transverse crosssection of the tubing hanger is substantially smaller than the transverse cross-section of the bore, as would be the case when a tubing hanger spider is used to support the tubing hanger. In such an instance, for the anchor screws to be effective, they would have to be run inwardly for a substantial distance and a substantial number of turns before the inner ends thereof would engage with the tubing hanger. Additionally, in such event, there would be no positive latching or coupling between the tubing hanger and its spider, as would be desirable and beneficial under many circumstances.

With the foregoing in mind, it is, therefore, an object of the present invention to provide a new and improved latching arrangement for coupling a pair of telescopically arranged members in a well installation, such latching arrangement being selectively releasable to enable one of said members to be telescopically withdrawn from the other.

A further and more specific object of the invention is to provide a latching means for releasably connecting a tubing hanger and a tubing hanger spider and to additionally provide an actuating means which can selectively control the operation of the latching means.

Another object of the invention is to provide a wellhead assembly wherein slight inward movement of actuating screws in the head member effects a latching between a tubing hanger and its supporting spider and wherein slight outward movement of the actuating screws enables the tubing hanger to be unlatched from and subsequently withdrawn from its supporting spider.

Another object of the invention is to provide a new and improved latching means for selectively latching and unlatching a pair of members in a well installation and to further provide an actuating means which can be quickly and simply manipulated to control the condition of the latching means.

Other objects, advantages and salient features of the present invention will become apparent from the following detailed description, which, taken in conjunction with the annexed drawings, discloses a preferred embodiment thereof.

Referring now to the drawings, which form a part of the specification:

FIG. 1 is a vertical sectional view through a well installation in accordance with the principles of the present invention;

FIG. 2 is an enlarged fragmentary sectional view of the latching means and actuating means of the present invention, showing the parts in latched condition; and

FIG. 3 is a fragmentary view, similar to FIG. 2, but showing the parts in unlatched condition.

Referring now to FIG. 1 in greater detail, there is shown therein a well installation including a combination of components generally designated 20. Such components include a first member generally designated 22 which forms the head member, a second member generally designated 24 which forms the tubing hanger and an inte mediate member generally designated 26 which forms the tubing hanger spider. The combination additionally includes a latching means generally designated 28 and an actuating means generally designated 30.

The head member 22 has a through bore 32 formed centrally therein, such bore extending axially through the head member and in its usual orientation, the axis of the bore is vertical. An inwardly directed frusto-conical shoulder 34 is provided along the length of the bore 32, and at its lower end, the bore is provided with screw threads 36 which receive meshing screw threads 38 formed along the top joint of a casing string 40. In this manner, the casing string 40 is suspended from the head member 22.

A casing hanger 42 represents the first component which is installed in the head member 22 during assembly of the well installation. The casing hanger 42 has a main body 44 of a smaller transverse cross section than that of the bore 32 in the head member. However, a circumferentially extending flange 46 is integrally formed intermediate the axial extent of the body 44 and and the outer peripheral surface of this flange 46 is substantially the same size as the bore 32 in the head member, although it must be slightly smaller to enable the casing hanger 42 to be lowered. The lower edge 48 of the flange 46 is chamfered or tapered inwardly to provide a shoulder which abuts against the inwardly directed shoulder 34 on the head member. The casing hanger 42 is provided with a vertical through bore 50 co-axial with the bore 32 of the head member. The lower portion of this bore is provided with screw threads 52 which receive meshing screw threads 54 from the top joint of a further casing string 56 which is thus suspended by the casing hanger 42. The upper portion of the bore 50 is provided with screw threads 58 into which a handling string can be threaded so that the casing hanger 42 and the casing string 56 suspended therefrom can be lowered through the bore of the head member until the shoulder 48 on the casing hanger seats upon the shoulder 34 of the head member. At this time, the handling string can be unthreaded and removed, as is customary.

The next member which is installed in the assembly is a sealing ring 60 whose lower end abuts against the top of the flange 46 on the casing hanger 42. The thickness of the sealing ring 60 is such that its outer surface engages against the walls of the bore 32 and the head member, with sealing O-rings 62 being provided at the interface. The inner surface of the ring member 60 engages, at its lower end, with the upper portion of the casing hanger body 44, and once again, sealing O-rings 64 are provided at the interface. An inwardly directed tapered frusto-conical shoulder 66 is provided at the upper end of the sealing ring 60, such shoulder merging into a substantially flat upper surface 68 on the ring. If desired, suitable anchor screws, not shown, can be threaded through the walls of the head member 22 so that their inner ends abut against the shoulder 66 to compress the sealing ring 60 and to prevent the same from being blown upwardly by pressure.

The next item which is installed in the assembly is the tubing hanger spider 26 which includes reduced diameter upper and lower portions 70 and 72 respectively and an enlarged intermediate portion 74. The bottom edge of the lower portion 72 seats upon the top 68 of the sealing ring 60, thereby serving to position the spider within the bore 32 of the head member. The intermediate portion 74 is enlarged to substantially the same cross-sectional dimension as the bore 32 although, by necessity, the portion 74 must be somewhat smaller to permit the spider to be lowered into the bore. A pair of circumferentially extending sealing O-rings 76 are carried about the periphery of the intermediate portion 74 to seal against the walls of the bore 32.

At this point, it should be explained that the conventional outlets are provided for communication interiorly of the casing strings 40 and 56. A pair of outlets 71 and 73 are radially tapped through the walls of the head member 22. The outlet 71 communicates with a flow port 75 formed axially through the flange 46 of the casing hanger 42 to effect flow to and from the casing string 40. The outlet 73 communicates with a flow port 77 formed radially through the lower portion 72 of the spider 26 to effect flow to and from the casing string 52. It should also be noted that at this point that although the casing hanger 44 which suspends the casing string 56 is shown as a mandrel suspension means, it is also possible and entirely acceptable to use slip means for suspending the casing string 56. One suitable form of slip means for accomplishing this purpose is described in US Patent No. 3,266,823, dated Aug. 16, 1966, in the name of William W. Word, Jr. and Claude R. Neilon.

Returning once again to the tubing hanger spider 26, it will be noted that such spider is provided with a vertical through bore 78 co-axial with the bore 32 through the head member. Within the lower portion 72 of the tubing hanger spider, the bore 78 converges inwardly by means of an inwardly and downwardly directed frusto conical shoulder 80. A reduced diameter bore portion 82 then extends from the inner edge of the shoulder to the bottom of the spider 26.

Once the spider 26 has been so installed in the assembly, the tubing hanger 24 can be lowered into position. As can be seen from FIG. 1, the tubing hanger is of such transverse cross-sectional dimension so as to permit the same to be lowered into the bore 78 in the tubing hanger spider 26. The main body 84 of the tubing hanger is of this dimension although a reduced diameter portion 86 is provided at the lower end of the tubing hanger. A downwardly and inwardly tapering frusto-conical shoulder 88 extends between the portions 84 and 86 and this shoulder seats upon the inwardly directed shoulder 80 of the tubing hanger spider when the tubing hanger has been lowered to its lowermost vertical position. At this time, as can be seen, the lower most portion 86 of the tubing hanger fits through the bore portion 82 of the spider and is disposed at least partially within the opening in the center of the sealing ring 60. A single centered production or tubing string 90 is suspended from the tubing hanger 24 in the illustrated embodiment hereof, but it will be understood that this showing is merely for simplicity of illustration. If desired, multiple tubing strings 90 can be utilized, and likewise, the tubing string can be oiTset from the central axis of the tubing hanger to permit passage of an auxiliary device, such as a power cable. Although not illustrated, it will be understood that the tubing hanger 24 is provided with the conventional through bore which, in the illustrated embodiment, is coaxial with the bore 32 of the head member. The tubing string 90 can be suspended from the tubing hanger by means of a suitable screw thread engagement, such as that described in connection wtih the casing strings 40 and 56.

Adjacent the upper end of the bore through the tubing hanger 24, a threaded portion 92 is provided for receiving a handling string which is used for lowering the tubing hanger and its suspended tubing string into position until the shoulder 88 seats upon the shoulder 80 on the tubing hanger spider. Then, the handling string can be unscrewed from the bore portion 92 and removed.

At this point, except for the latching means 28 and actuating means 30, which will be described in detail hereinafter, the major components of the combination 20 will have been installed and assembled. As can be seen, a bonnet 94 is provided in overlying relationship to the head member 22 and the components disposed within the bore thereof. An annular recess 96 is provided along the bottom of the bonnet 94 and a confronting annular recess 98 is provided along the top of the head member 22. An annular sealing gasket 100 is interposed between the bonnet and the head member, as illustrated, with its upper edge engaged in the recess 96 and its lower edge engaged in the recess 98. The lower peripheral edge of the bonnet 94 is formed as an outwardly directed flange 102 and a recess 104 is formed adjacent the top of the body member 22 to thus set off a similar, but oppositely directed outwardly directed flange 106 on the head member. Clamp means 108 of a generally C-shaped cross-sectional configuration are connected across the flanges 104 and 106 to thus lock the bonnet 94 onto the head member 22.

The bonnet is provided with a central through bore 110, co-axial with the bore through the tubing hanger 24. A slightly enlarged recess 112 is formed at the top of the tubing hanger, co-axial with the bore therethrough, and a confronting similarily shaped recess 114 is formed at the bottom of the bonnet 94, co-axial with the bore therethrough. A connecting sleeve 116 is thus positioned between these recessed portions 112 and 114, with the lower portion of the sleeve disposed in the recess 112 and the upper portion thereof disposed in a recess 114. This sleeve 116 provides a flow transition from the bonnet to the tubing hanger and hence to the tubing string 90 suspended therefrom. The sleeve 116 may be provided with an external O-ring sealing means 118 in the recess 112 and a similar O-ring sealing means 120 in the recess 114. An alternative form of sleeve member, and a fuller discussion of a sleeve member of this type are found in my prior US, Patent No. 3,062,565, dated Nov. 6, 1962. A threaded portion 122 is provided at the upper part of the bonnet bore 110 to receive a suitable master valve or Christmas tree assembly which connects with v the tubing string 90.

For a fuller understanding of the latching means 28 and the actuating means 30, atttention is directed to FIGS. 2 and 3 wherein the means are shown in somewhat larger illustration. The latching means 28 includes a pair of latching components, the first of which is a circumferentially extending latching groove 130 formed peripherally about the tubing hanger 24 substantially intermediate its upper end and its shoulder 88. The central portion of the latching groove means 130' is a substantially cylindrical axially extending flat section, but the upper and lower edges thereof are formed by oppositely directed frusto-conical surfaces 132 and 134 respectively. A pair of circumferentially extending sealing O-rings 136 are provided along the body portion 84 of the tubing hanger 24, between the lower most shoulder 134 of the latching groove and the shoulder 88 which seats the tubing hanger on its spider. The purpose of these O-rings 136 is to seal against the bore 78 through the tubing hanger spider.

The other latching component is a series of radially movable pin means generally designated 138, freely movable in the spider 26. Each pin means 138 includes an enlarged head portion 140 having a chamfered frustoconical surface 142 extending from its periphery to the outer surface 144 thereof. A shank portion 146, preferably cylindrical, extends from the underside of the head 140 toward the latch groove. The inner end of each pin means 138 includes a chamfered frusto-conical surface 148 extending from the periphery of the shank to the flat bottom 150 of the pin.

For an understanding of how the spider 26 slidably supports the pin means 138, it will first be noted that a radially directed shoulder 152 is provided at the juncture of the upper portion 70 and intermediate portion 7-4 of tubing hanger spider 26. A countersunk portion 154, which can best be seen in FIG. 3, is provided above the shoulder 152 with the diameter of the countersunk portion being suflicient to accommodate the head 140 of the pin means, but with the depth thereof being such that the chamfered portion 142 of the head remains disposed in the annular channel between the exterior of the spider top portion 70 and the walls of the bore 32, even when the head is fully seated in the countersunk portion 154.

A radial through bore 156 extends from the countersunk portion to the axial bore 78 of the spider to slidably accommodate the shank portion 146 of the pin means.

The size of the pin means 138 is correlated with the depth of the countersunk portion 154 which accommodates the head of the pin and with the radial thickness of the annular recess between the walls of the bore 32 and the exterior of the spider upper portion 70. Thus, as can be seen by a comparison of FIGS. 2 and 3, when the head is fully seated within its countersunk receiving portion 154, the inner end 148 of the pin extends into the bore 78 of the spider 26 and hence into the latching groove 130 which is juxtaposed to the inner end of the pin. When the pin is in its radial outward position, as shown in FIG. 3, so that the flat inner end thereof is substantially co-extensive with the walls of the bore 78, preferably at least a small portion of the head 140 still remains disposed within the countersunk portion 154. The number of pin means 138 can be varied, as desired, but such pin means should be spaced at equal locations circumferentially about the spider 26.

Turning now to the actuating means 30 such actuating means includes a series of actuating screws or projection means generally designated 160, threaded radially through the walls of the head member 22. Each actuating screw includes a threaded portion 162 engageable with a threaded bore 164 extending radially through the walls of the body member 22 at an axial location above the latching means 28. As shown in FIG. 1, the shank 166 of the screw extends radially outward through a packing 168 and a packing energizing nut 170 which, when tightened, compresses the packing 168 to prevent fluid from escaping therepast. The recess 172 can be provided at the outer end of the shank 166 for receiving a tool or the like which enables the actuating screw 160 to be selectively run into and out of the bore 32 of the body member. The actuating screw 160 includes an unthreaded inner end portion 174 which merges into a chamfered frusto-conical surface 176. The actuating screws can be selectively rotated in a clockwise and counterclockwise direction to thus selectively move this tapered section 176 at the end of the screws into and out of the bore 32 in the head member.

Finally, an actuating gland 180 which forms a part of the actuating means 30 is freely mounted within the recess between the walls of the bore 32 and the exterior of the top 70 of the spider 26. The actuating gland 180 is of annular configuration and is provided with an inner surface 182 engageable with the sloped surface 142 on the head of the pin means. The actuating gland 180 is also provided with an exterior surface 184 engageable with the sloped section 176 at the inner end of the actuatlng screws 160 which are circumferentially spaced at equal intervals about the head member 22. A suitable ring 186, such as an O-ring, is carried by the upper portion 70 of the spider 26 at an axial or vertical location above the actuating means 30.

Although it will be apparent from the drawings, it will nevertheless be stated herein that the various portions of the actuating and latching means where one surface engages with the other form compatible and cooperating cam surfaces. Thus, the slope of the inner end 148 on the pin means corresponds with the slope of the lower shoulder 134 of the latching groove so that the surfaces 134 and 148 form cooperating cam surfaces. Similarly, the inner surface 182 of the actuating gland is sloped at substantially the same angle as the surface 142 at the head of the pin means so that, once again, the surfaces 142 and 182 form cooperating cam surfaces. Finally, the outer surface 184 of the actuating gland 180 is sloped at substantially the same angle as the inner end 176 of the actuating screws 160 so that the surfaces 184 and 176 form cooperating cam surfaces.

With the foregoing explanation in mind, it will be understood that the actuating screws 160 are necessarily run out or retracted when the tubing hanger spider 26 is lowered into position within the bore of the head member. Then, once the tubing member 24 has been inserted within the spider, the screws 160 can be radially run inward or advanced so that their inner ends project into the bore 32. As the screws are being run in this manner, the surface 176 at the inner end thereof cams against the outer surface 184 of the actuating gland 180 to move the actuating gland axially downwardly. This downward movement of the actuating gland 180, in turn, causes the inner surface 182 of the gland to cam against the sloped surface 142 on the head of the pin means 138, thus moving the pin means radially inwardly until the flat face 150 on the end of the pin enters the latching groove 130 and until the sloped shoulder 148 at the end of the pin engages against the lower shoulder 134 of the groove. At this time, further advancing of the screws 160 would only serve to compress the actuating gland 180, and hence rotation of these screws can be terminated. It will, however, be understood that at this time the latching means has firmly connected the tubing hanger 24 with the tubing hanger spider 26. The connection of the pins 138 into the latching groove additionally serves to prevent the tubing hanger 24 from being blown upwardly by pressure and similarly, the screws 160 serve to prevent the tubing hanger spider from being blown upwardly by such pressure.

Assuming now that it becomes desirable or necessary to remove the tubing hanger 24 and the tubing string 90 supported thereby, or blow out preventers or control equipment, such action would naturally be commenced by removing the clamps 108 and the bonnet 94, with the sleeve 116 also being removed at this time. Then, a handling string can be threaded into the threaded bore 92 adjacent the top of the tubing hanger to lift the same out of the well installation. However, before such lifting can take place, the tubing hanger must be unlatched from its spider and to commence this unlatching operation, the actuating screws .160 are retracted or run outwardly to substantially the position shown in FIG. 3 where the inner ends thereof no longer project into the bore 32 for any distance. Then, the tubing hanger is lifted upwardly by the handling string and as it is lifted, the camming action of the latch groove shoulder 134 on the inner end of the pins 138 serves to push such pins radially outward in the manner shown in FIG. 3. Such outward movement is permitted because the actuating gland 180 is no longer restrained by the screws 160 and can hence move axially upward as the pins move radially outward. The tubing hanger and the tubing string can then be removed and repaired, replaced, inspected or otherwise attended to and then can be reinstalled in the assembly in the manner described hereinbefore. If the inner ends of the pin should happen to project back into the bore 78 of the spider while the tubing hanger 24 is removed, this will not create a problem since, when the tubing hanger is reinstalled, the shoulder 88 adjacent the lower end thereof will contact the sloped ends 148 on the pins and cam the same back outwardly until the tubing hanger is fully lowered into position. Then, once again, the actuating screws 160 can be run inwardly to re-establish the latched condition.

After reading the foregoing detailed description, it should be apparent that the objects set forth at the outset of the specification have been successfully achieved by the present invention.

What is claimed is:

1. In a well installation, the combination comprising a first member having an axial bore therethrough;

a second member telescopically disposed with in said bore;

said second member having at least a portion of smaller transverse cross-section than the transverse cross-section of said bore; an intermediate member interposed and supported within said bore between said first member and said portion of said second member;

latching means operable to selectively latch and unlatch said second member and said intermediate member;

said latching means including:

a first latching component disposed upon and supported by said portion of said second member; and

a second latching component disposed upon and supported by said intermediate member in juxtaposition to said first latching component;

said second latching component comprising pin means mounted for free radial movement through said intermediate member to selectively engage said first latching component with said second latching component to establish a latched condition and to selectively disengage said first latching component from said second latching component to establish an unlatched condition;

actuating means independent of said latching means but cooperative therewith;

said actuating means being selectively operable to engage said first latching component with said second latching component to establish said latched condition, and also being selectively operable to permit said second latching component to disengage from said first latching component to establish said unlatched condition;

said actuating means including an annular member axially movable within said axial bore, said annular member having a frusto-conical upper cam surface and a frusto-conical lower cam surface;

said actuating means further including at least one radially movable projection member mounted on said first member axially above said pin means;

said projection member having an inner end portion which, when said projection member is advanced radially inwardly, moves into said bore and contacts said upper cam surface to cause said annular member to be axially lowered within said bore;

said axial lowering of said annular member bringing said lower cam surface thereof into contact with said pin means to advance said pin means radially inwardly and to thus establish said latched condition;

said second member being latched to said intermediate member when said latched condition is established, thereby preventing said second member from moving axially through said bore in said first member to fully separate said second member from said first and intermediate members;

said second member being unlatchable from said intermediate member when said unlatched condition is established, thereby enabling said second member to be moved axially through said bore in said first member and hence fully separated from said first and intermediate members.

2. The combination defined in claim 1 wherein said upper and lower frusto-conical cam surfaces are each directed downwardly and outwardly.

3. The combination defined in claim 1 wherein said first latching component is a groove means formed along said portion of said second member and wherein said pin means includes a portion which is releasably insertable in said groove means.

4. The combination defined in claim 3 wherein said pin means includes an inner end portion insertable in said groove means and an outer end portion engageable with said lower cam surface of said annular member.

5. The combination defined in claim 4 wherein said projection member inner end portion has a sloped cam surface tgooperative with said upper cam surface of said annular member and wherein said outer end portion of said pin means has a sloped cam surface cooperative with said lower cam surface of said annular member.

6. The combination defined in claim 1 wherein a plurality of projection members are provided, each including a threaded portion radially movable through a threaded bore in said first member.

7. The combination defined in claim 1 wherein said first member comprises a head member, said second member comprises a tubing hanger member and said intermediate member comprises a tubing hanger spider.

8. The combination defined in claim 7 wherein said tubing hanger spider includes a sloped supporting houlder means and wherein said tubing hanger member includes a corresponding sloped shoulder means which rests upon said spider shoulder means when said tubing hanger member reaches its lowest axial position in said bore, said latching means, when in said latched condition, preventing said tubing hanger member from being raised from said 10 lowest axial position, said latching means, when in said unlatched condition, permitting said tubing hanger member to be raised from said lowest axial position.

References Cited UNITED STATES PATENTS THOMAS F. CALLAGHAN, Primary Examiner US. Cl. X.R. 

